The invention relates to a flap arrangement, especially for a ventilation or air conditioning system for vehicles. More particularly, the present invention relates to a flap arrangement in which the articulation points on the flaps are so determined that the radius of a circular path described by these points during pivoting of the flaps is of equal size and an effective straight line connecting the points rotates about a center located approximately in the middle between the pivot axes.
A known flap arrangement with two oppositely pivoting flaps is arranged in an air-guide housing of an air-conditioning system. The two flaps are separated from one another by a partition wall mounted centrally between the flaps. The flaps can be pivoted continuously out of a closing position, in which they bear against horizontal flap stops and each separate an air-mixing space from a distributor space, into a maximum open position, with the pivoting directions of the flaps being opposite to one another. For reasons of space, the coupling linkage is arranged inside of the air-guide housing, thus making it necessary to provide in the partition wall an orifice which is preferably placed in the region of the distributor spaces located above the mixing spaces. To keep this orifice as small as possible, the pivoting geometry of the flaps is such that the end positions of each linkage articulation point on each flap, i.e. the point moving along a circular path when the flaps pivot, are located on a straight line extending perpendicularly relative to the partition wall when the flap is in its two end positions.
Such a known pivoting geometry, however, results in an error of synchronism between the flaps, so that, unequal quantities of air are fed into the two distributor spaces in a desired leakage-air or intermediate position of the flaps.
An object on which the present invention is based is to substantially improve a flap arrangement with oppositely moving flaps such that a synchronism of the flaps is ensured over the entire pivoting range; that is to say, the pivoting of the driven flap through a specific pivoting angle adjusts the respective coupled flap through a pivoting angle of the same amount.
In a flap arrangement according to the present invention, the foregoing object has been achieved by determining the articulation points on the flaps such that, on one hand, the radius of the circular path described by the points during pivoting of the flaps of equal size and, on the other hand, an effective straight line connecting the two articulation points rotates about a center of rotation located approximately midway between the pivot axes.
As a result of the arrangement of the linkage articulation points on the flaps in accordance with the present invention, the coupling linkage engages with the same lever arm on each flap in every adjustment position of the flaps. During the rotation or pivoting of the driven flap, this lever arm or effective spacing is increased or reduced uniformly on each flap and ensures a transmission ratio of 1:1, thereby guaranteeing the intended synchronism of the two flaps.
In a presently preferred embodiment of the invention, the coupling linkage is formed by a tripled angled portion rod which, when the flaps are in the maximum opening position, has its first angled portion located near the pivot axis of the coupled flap, its second, identically directed angled portion located approximately in the middle between the two pivot axes and its third angled portion directed oppositely to the other two angled portions and located approximately in the middle between the two pivot axes and its third angled portion is directed oppositely to the other two angled portions located approximately at the articulation point of the driven flap. The articulation point of the driven flap is arranged above its pivot axis, and the articulation point of the coupled flap is arranged below its pivot axis. Such a configuration makes it possible to accommodate the coupling linkage in a very confined space, and at the same time, the necessary perforation in a partition wall arranged between the flaps for guiding the rod through need be only of relatively small size.
According to a further embodiment of the present invention, the rod carries a threaded portion at its end facing the driven flap and is screwed in a rotary body. The rotary body rests by way of an annular flange in a vertical slot of an approximately horizontally arranged holding fork which is itself held rotatably by two laterally projecting pivot pins in bores of a flap shackle formed from two webs extending parallel to and at a distance from one another. This affords a possibility of adjusting the coupled flap, the relative position of which in relation to the driven flap can be adjusted over a wide range. At the same time, the synchronism of the flaps is ensured in all the adjustment positions.
In one embodiment of the present invention, the rotary body has a concentric internally threaded bore for screwing in the threaded portion of the rod. The bore is stepped in the mouth region pointing towards the third angling of the rod and has a larger bore diameter. This step allows a wider adjustment range, since in the final phase of adjustment, the third angled portion of the rod can penetrate into this step region, without impeding the adjusting movement of the rod in the rotary body.